Download CCNA 200-301 Exam Q&A: VLANs, Switching, and EtherChannel and more Exams Computer Science in PDF only on Docsity!
CCNA 200-301 questions with correct answers
What is the primary purpose of a VLAN? CORRECT ANSWER To create a broadcast domain; enable segmentation or isolation of broadcast traffic Unassigned Cisco switch ports remain in which VLAN? CORRECT ANSWER VLAN 1 Do VLANs prevent broadcast storms? CORRECT ANSWER No, they minimize the size and effect of the broadcast storm on neighbor switches and hosts What are four advantages to using VLANs? CORRECT ANSWER 1. Enable access to network services based on logical requirements
- Network security is optimized with VLANs that enable managing and filtering sensitive traffic from other network traffic
- Bandwidth efficiency is accomplished through segmenting traffic into smaller broadcast domains
- Easier add/move/delete administration of endpoints on a network and scalability for larger enterprise deployments What is the Layer 2 Broadcast Destination Address? CORRECT ANSWER FFFF.FFFF.FFFF What is the Layer 3 Broadcast Destination Address? CORRECT ANSWER 255.255.255. What is VLAN 1 used for and can it be deleted? CORRECT ANSWER Management Traffic; it cannot be deleted
What is the normal VLAN range? CORRECT ANSWER VLAN 2 - 1001 What is the extended VLAN range? CORRECT ANSWER VLAN 1006 - 4094 What VLANs are auto-created and cannot be deleted? CORRECT ANSWER VLAN 1, 1002 - 1005 What VLANs cannot be pruned from a trunk? CORRECT ANSWER VLAN 1006
- 4094 How many VLANs can be assigned to a switch access port? CORRECT ANSWER Only one VLAN unless you are connecting an IP phone What commands would you use to setup a switch access port with an IP phone? CORRECT ANSWER interface <interface#/#> switchport mode access switchport access vlan # switchport voice vlan # Where is the switch VLAN configuration stored? CORRECT ANSWER vlan.dat file What commands would you use to globally create and name a VLAN? CORRECT ANSWER vlan # name <name_of_vlan> What is the default switch port mode? CORRECT ANSWER Access port
- Create separate collision domains per switch port
- Create separate broadcast domains per VLAN What method was used for detecting Ethernet collisions on older hubs and bridges? CORRECT ANSWER Carrier Sense Multiple Access Collision Detection (CSMA/CD) How many separate MAC address table does a switch create? CORRECT ANSWER A switch creates a separate MAC address table for each configured VLAN What command lists the contents of the MAC address table for a switch? CORRECT ANSWER show mac address-table When does a switch begin MAC address learning? CORRECT ANSWER When a switch is first started and connected hosts start sending frames? Also triggered when the aging time expires for an address What is the default time that a switch removes MAC address table entries? CORRECT ANSWER 300 seconds How do you disable MAC address table aging? CORRECT ANSWER Configure the MAC aging timer to zero What are the steps when a host sends data to a server on the same VLAN for the first time? CORRECT ANSWER 1. Switch adds the source MAC address of incoming frame if it is not listed in the MAC address table
- Switch does a MAC address table lookup for the destination MAC address
- Switch floods a frame using FFFF.FFFF.FFFF as destination MAC address out all switch ports except the port where the source MAC address was learned
- Server wit the assigned MAC address responds with a frame that lists the MAC address
- Switch updates the MAC address table with the MAC address of the server; That is the destination MAC address for frames sent from the host
- Switch forwards the frames from the host to the server based on the switch port assigned to the server What is Cut-Through Switching? CORRECT ANSWER It is a technique that optimizes performance by examing only the first 6 bytes (destination MAC address) of an Ethernet frame before making a forwarding decision. The switch does a MAC address table lookup for the destination MAC address and forwards the frame. What is the advantage of Cut-Through Switching? CORRECT ANSWER The forwarding decision is made before all of the frame arrives and thereby minimizes latency What is Store-and-Forward Switching? CORRECT ANSWER Traditional switching where the frame is not forwarded until all of the frame has arrived. The switch copies the frame to memory before examining the destination MAC address and forwarding the frame. What is CEF? CORRECT ANSWER Cisco Express Forwarding: Layer 3 switching technique that creates FIB and adjacency tables for optimized forwarding. It is only available on routers and switch platforms with routing enabled and the required hardware What is an FIB? CORRECT ANSWER Forwarding Information Base: Used by CEF to mae IP destination prefix-based switching decisions. Conceptually similar
What is the purpose of VLAN pruning? CORRECT ANSWER To permit or deny VLANs across a switch trunk What is the Cisco default for VLAN pruning CORRECT ANSWER To allow all VLANs across the trunk What command sets a range of VLANs to an interface? CORRECT ANSWER switchport trunk allowed vlan <#>-<#> What are the three modes of DTP? CORRECT ANSWER nonegotiate, desirable, auto Is DTP enabled by default on switch ports? CORRECT ANSWER Yes What does a switch port configured with desirable mode do? CORRECT ANSWER Actively sends DTP frames to negotiate trunk with neighbor switch What is the operation of switchport mode access? CORRECT ANSWER Access port only (no trunk) - only one VLAN, two if you include a Voice VLAN What is the operation of switchport mode trunk? CORRECT ANSWER Trunk statically formed and no DTP frames sent What is the operation of switchport mode dynamic auto? CORRECT ANSWER Listens for DTP requests
What is the operation of switchport mode dynamic desirable? CORRECT ANSWER Listens and sends DTP requests What is the operation of switchport nonegotiate? CORRECT ANSWER Disables DTP What intervals are DTP frames sent? CORRECT ANSWER One second intervals during negotiation and every 30 seconds after that DTP auto mode - auto mode CORRECT ANSWER Default, results in no trunk DTP auto mode - desirable mode CORRECT ANSWER Trunk negotiated DTP desirable mode - desirable mode CORRECT ANSWER Trunk negotiated What does EtherChannel do? CORRECT ANSWER Bundles multiple physical switch links between switches into a single logical link. What is EtherChannel also referred as? CORRECT ANSWER Switch Port Aggregation What are the advantages of EtherChannels? CORRECT ANSWER Fault tolerance (redundancy) and high speed connectivity between switches What is the maximum number of ports Cisco switches support to a single EtherChannel bundle? CORRECT ANSWER 8 ports
What is a Layer 3 port channel? CORRECT ANSWER Routed logical interface comprised of EtherChannel access ports or trunk ports What is Active mode in LACP? CORRECT ANSWER The active end of the group sends out a LACP frame and initiates the negotiation to form the EtherChannel. Both ends could be active and the result will be the same What is Passive mode in LACP? CORRECT ANSWER Does not initiate the negotiation, it just responds to LACP packets initiated by the other end. If both ends are passive, the EtherChannel would bot be formed What is PAgP? CORRECT ANSWER Port Aggregation Protocol: Cisco proprietary networking protocol, which is used for the automated, logical aggregation of Ethernet switch ports What is the default mode for LACP? CORRECT ANSWER Passive Mode What is the default mode for PAgP? CORRECT ANSWER Auto Mode What layer of the TCP/IP model does HTTP belong? CORRECT ANSWER Application Layer What layer of the TCP/IP model does POP3 belong? CORRECT ANSWER Application Layer What layer of the TCP/IP model does SMTP belong? CORRECT ANSWER Application Layer
What layer of the TCP/IP model does TCP and UDP belong? CORRECT ANSWER Transport Layer What layer of the TCP/IP model does ICMP belong? CORRECT ANSWER Internet Layer What does the Application Layer define? CORRECT ANSWER Does not define the applications itself, but it defines services that applications need. The Application Layer provides an interface between software running on a computer and the network itself. What does the return code 200 mean in an HTTP header? CORRECT ANSWER OK What does the return code 404 mean in an HTTP header? CORRECT ANSWER Not found What layers of the OSI model do not exist in the current TCP/IP model? CORRECT ANSWER Session and Presentation Layers (5 and 6) What standard is 802.3? CORRECT ANSWER Ethernet In an Informal IEEE Standard Name, what does the T stand for (example: 1000BASE-T)? CORRECT ANSWER Unshielded Twisted Pair (UTP) In an informal IEEE Standard Name, what does the X stand for (example: 1000BASE-LX)? CORRECT ANSWER Fiber
What is a Small Form Pluggable Plus (SFP+)? CORRECT ANSWER Same size as the SFP, but used on 10-Gbps interfaces How many pairs of wires do the 10BASE-T and 100BASE-T use? CORRECT ANSWER 2 pairs What pins do Ethernet NIC transmitters use? CORRECT ANSWER The pair connected to pins 1 and 2 What pins do Ethernet NIC receivers use? CORRECT ANSWER The pair connected to pins 3 and 6 What pins do Switch transmitters use? CORRECT ANSWER The pair connected to pins 3 and 6 What pins do Switch receivers use? CORRECT ANSWER The pair connected to pins 1 and 2 What cable would you use to connect a computer to a switch? CORRECT ANSWER Straight through cable What devices transmit on pins 3 and 6? CORRECT ANSWER Switches and Hubs What devices transmit on pins 1 and 2? CORRECT ANSWER NICs, Routers, APs When would you use a Crossover Cable? CORRECT ANSWER When the endpoints transmit on the same pair
When would you use a Straight through Cable? CORRECT ANSWER When the endpoints transmit on different pairs What is auto-mdix? CORRECT ANSWER In Cisco switches, it notices when the wrong cable is used and automatically changes its login to make it work. What is the maximum length of many UTP-based Ethernet standards? CORRECT ANSWER 100 meters What are the layers of a fiber cable inside going outward? CORRECT ANSWER Core, Cladding, Buffer, Strengthener, Outer Jacket What are the layers of a fiber cable outside going in? CORRECT ANSWER Outer Jacket, Strengthener, Buffer, Cladding, Core What is the light source for a fiber cable? CORRECT ANSWER Optical Transmitter What is the purpose of the cladding in a fiber cable? CORRECT ANSWER Reflect light back into the core Which mode of fiber cable has around one-fifth the diameter of the other mode? CORRECT ANSWER Single-Mode Fiber What type of light source does Multimode Fiber use? CORRECT ANSWER Light Emitting Diode (LED) What type of light source does Single-Mode Fiber use? CORRECT ANSWER Laser
How many bytes and purpose of the Preamble in an Ethernet header? CORRECT ANSWER 7 bytes - synchronization How many bytes and purpose of the Start Frame Delimiter (SFD) in an Ethernet header? CORRECT ANSWER 1 byte - Signifies that the next byte begins the destination MAC address field How many bytes and purpose of the Destination MAC Address in an Ethernet header? CORRECT ANSWER 6 bytes - Identifies the intended recipient of the frame How many bytes and purpose of the Source MAC Address in an Ethernet header? CORRECT ANSWER 6 bytes - Identifies the sender of the frame How many bytes and purpose of the Type in an Ethernet header? CORRECT ANSWER 2 bytes - defines the type of protocol listed inside the frame; today, most likely identifies IPv4 or IPv How many bytes and purpose of the Data and Pad in an Ethernet frame? CORRECT ANSWER 46-1500 bytes - Holds data from a higher layer, typically a packet. The sender adds padding to meet the minimum length requirement for this field What is the Maximum Transmission Unit (MTU)? CORRECT ANSWER Defines the maximum Layer 3 packet that can be sent over a medium How many bytes and purpose of the Frame Check Sequence (FCS) in an Ethernet trailer? CORRECT ANSWER 4 bytes - Provides a method for the receiving NIC to determine whether the frame experienced transmission errors
How many bytes are the Ethernet header and trailer? CORRECT ANSWER Header = 22 + Trailer = 4 == 26 bytes What does the FCS do in the Ethernet Trailer? CORRECT ANSWER Gives the receiving node a way to compare results with the sender, to discover whether errors occurred in the frame How does the FCS perform in the Ethernet Trailer? CORRECT ANSWER Sender applies a complex math formula to the frame before sending it, storing the result of the formula in the FCS field. The receiver applies the same formula to the received frame. If the results are different, an error occurred, and the receiver discards the frame What do WAN technologies define? CORRECT ANSWER The physical (Layer 1) and data link (Layer 2) protocols used to communicate long distances What duplex is a Leased Line link? CORRECT ANSWER Full-Duplex Why are they called Leased Lines? CORRECT ANSWER The fact that the telco company does not own the line but instead pays a monthly lease fee to use it What are other names used for Leased Lines? CORRECT ANSWER Leased Circuit, Circuit, Serial Line, Serial Link, Point-to-point link, Point-to-point line, WAN link What is a Private Line (WAN)? CORRECT ANSWER A line that data sent over it cannot be copied by other telco customers, so the data is private What is the transmit speed of a T1 line? CORRECT ANSWER 1.544 Mbps
What is the PoP? CORRECT ANSWER Point of Presence: Nearby SP location that connects to the customer building What is EoMPLS? CORRECT ANSWER Ethernet over Multiprotocol Label Switching, a technology that can be used to create the Ethernet service for a customer How many bytes are in the IP header? CORRECT ANSWER 20 bytes What are EXEC commands? CORRECT ANSWER Commands that can be used in either User EXEC mode or Enable EXEC mode How many commands are stored in the history buffer by default? CORRECT ANSWER 10 commands Where is the running config stored? CORRECT ANSWER RAM or DRAM What is Flash Memory? CORRECT ANSWER Either a chip inside the switch or a removable memory card, flash memory stores fully functional Cisco IOS images and is the default location where the switch gets its Cisco IOS at boot time; also can be used to store any other files including backup copies of config files What is ROM? CORRECT ANSWER Stores a bootstrap, or boothelper, program that is loaded when the switch first powers on. This bootstrap program then finds the full Cisco IOS image and manages the process of loading Cisco IOS into RAM, at which point Cisco IOS takes over operation of the switch What is NVRAM? CORRECT ANSWER Non-volatile RAM, stores the initial or startup configuration file that is used when the switch is first powered on and when the switch is reloaded
What is the Content-Addressable Memory (CAM) table? CORRECT ANSWER The MAC Address Table What are the default settings of a Cisco Catalyst Switch? CORRECT ANSWER - Interfaces are enabled by default
- All interfaces are assigned VLAN 1
- 10/100 and 10/100/1000 interfaces use autonegotiation
- MAC learning, forwarding, and flooding logic works
- STP is enabled What command is used to show the dynamically learned MAC addresses? CORRECT ANSWER show mac address-table dynamic What command removes the VLAN configuration details CORRECT ANSWER delete vlan.dat What is the default aging timer for a MAC Address table? CORRECT ANSWER 300 seconds What does a switch do when the MAC Address table is full? CORRECT ANSWER Times out the oldest record in the table What does the login command do on a line interface? CORRECT ANSWER Tells IOS to enable the user of a single shared password with no username on this line, so that the switch asks the user for the password
